Examples of Applied Control Types
Section
5-2
161
5-2 Examples of Applied Control Types
This section shows examples of applied control types when controlling
special control targets.
As the function blocks of the Loop Control Unit can be combined as desired
(excluding restrictions on the number of function blocks according to function
block address), use this feature to build a control system suited to your
particular control requirements.
The following table shows the relationship between example control types
corresponding to special control targets and the purpose of the control.
Control purpose
Control type example
Page
Suppression of disturbance
(on secondary loop)
Adaptation to dead time from
secondary through to primary loop
Cascade control
162
Suppression of disturbance
(on primary loop)
Feedforward control
165
Suppression of disturbance
(on primary and secondary loops)
C feedforward control
162/165
Adaptation to mutual interaction
between processes
Non-interacting control (a type of
feedforward control)
167
Sample PI control
168
Adaptation to dead time
Dead time compensation
170
Adaptation to changes in dead time Variable sample cycle control
169
Note
"Special control targets" here refer to the following.
Processes having a prolonged dead time
Processes who dynamic or static characteristics change
Processes whose dynamic characteristics are not the "regular dead time +
first-order lag"
Processes whose non-linearity of dynamic or static characteristics is large
Processing involving a large number of variables and strong mutual
interaction
However, design your system taking into consideration the possibility that the
control target cannot be completely controlled by this Loop Control Unit (take
into consideration that functions for observing the characteristics of the
control target are required).